From a9849560c55e9e4ab9c53d073363dd6e19ec06ef Mon Sep 17 00:00:00 2001 From: Jia Zhu Date: Sun, 18 Sep 2022 12:34:54 +0800 Subject: [PATCH] erofs: introduce a pseudo mnt to manage shared cookies Use a pseudo mnt to manage shared cookies. Signed-off-by: Jia Zhu Reviewed-by: Jingbo Xu Link: https://lore.kernel.org/r/20220918043456.147-5-zhujia.zj@bytedance.com Signed-off-by: Gao Xiang --- fs/erofs/fscache.c | 13 +++++++++++++ fs/erofs/internal.h | 1 + fs/erofs/super.c | 33 +++++++++++++++++++++++++++++++-- 3 files changed, 45 insertions(+), 2 deletions(-) diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c index 8a1be6077ca450..0480aaf44cb9a2 100644 --- a/fs/erofs/fscache.c +++ b/fs/erofs/fscache.c @@ -8,6 +8,7 @@ static DEFINE_MUTEX(erofs_domain_list_lock); static LIST_HEAD(erofs_domain_list); +static struct vfsmount *erofs_pseudo_mnt; static struct netfs_io_request *erofs_fscache_alloc_request(struct address_space *mapping, loff_t start, size_t len) @@ -432,6 +433,10 @@ static void erofs_fscache_domain_put(struct erofs_domain *domain) mutex_lock(&erofs_domain_list_lock); if (refcount_dec_and_test(&domain->ref)) { list_del(&domain->list); + if (list_empty(&erofs_domain_list)) { + kern_unmount(erofs_pseudo_mnt); + erofs_pseudo_mnt = NULL; + } mutex_unlock(&erofs_domain_list_lock); fscache_relinquish_volume(domain->volume, NULL, false); kfree(domain->domain_id); @@ -486,6 +491,14 @@ static int erofs_fscache_init_domain(struct super_block *sb) if (err) goto out; + if (!erofs_pseudo_mnt) { + erofs_pseudo_mnt = kern_mount(&erofs_fs_type); + if (IS_ERR(erofs_pseudo_mnt)) { + err = PTR_ERR(erofs_pseudo_mnt); + goto out; + } + } + domain->volume = sbi->volume; refcount_set(&domain->ref, 1); list_add(&domain->list, &erofs_domain_list); diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h index 93fc4ad61cfb01..0db56259160ca8 100644 --- a/fs/erofs/internal.h +++ b/fs/erofs/internal.h @@ -373,6 +373,7 @@ struct page *erofs_grab_cache_page_nowait(struct address_space *mapping, } extern const struct super_operations erofs_sops; +extern struct file_system_type erofs_fs_type; extern const struct address_space_operations erofs_raw_access_aops; extern const struct address_space_operations z_erofs_aops; diff --git a/fs/erofs/super.c b/fs/erofs/super.c index 884e7ed3d76068..ab746181ae0860 100644 --- a/fs/erofs/super.c +++ b/fs/erofs/super.c @@ -676,6 +676,13 @@ static const struct export_operations erofs_export_ops = { .get_parent = erofs_get_parent, }; +static int erofs_fc_fill_pseudo_super(struct super_block *sb, struct fs_context *fc) +{ + static const struct tree_descr empty_descr = {""}; + + return simple_fill_super(sb, EROFS_SUPER_MAGIC, &empty_descr); +} + static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc) { struct inode *inode; @@ -776,6 +783,11 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc) return 0; } +static int erofs_fc_anon_get_tree(struct fs_context *fc) +{ + return get_tree_nodev(fc, erofs_fc_fill_pseudo_super); +} + static int erofs_fc_get_tree(struct fs_context *fc) { struct erofs_fs_context *ctx = fc->fs_private; @@ -844,10 +856,21 @@ static const struct fs_context_operations erofs_context_ops = { .free = erofs_fc_free, }; +static const struct fs_context_operations erofs_anon_context_ops = { + .get_tree = erofs_fc_anon_get_tree, +}; + static int erofs_init_fs_context(struct fs_context *fc) { - struct erofs_fs_context *ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); + struct erofs_fs_context *ctx; + + /* pseudo mount for anon inodes */ + if (fc->sb_flags & SB_KERNMOUNT) { + fc->ops = &erofs_anon_context_ops; + return 0; + } + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); if (!ctx) return -ENOMEM; ctx->devs = kzalloc(sizeof(struct erofs_dev_context), GFP_KERNEL); @@ -874,6 +897,12 @@ static void erofs_kill_sb(struct super_block *sb) WARN_ON(sb->s_magic != EROFS_SUPER_MAGIC); + /* pseudo mount for anon inodes */ + if (sb->s_flags & SB_KERNMOUNT) { + kill_anon_super(sb); + return; + } + if (erofs_is_fscache_mode(sb)) kill_anon_super(sb); else @@ -907,7 +936,7 @@ static void erofs_put_super(struct super_block *sb) erofs_fscache_unregister_fs(sb); } -static struct file_system_type erofs_fs_type = { +struct file_system_type erofs_fs_type = { .owner = THIS_MODULE, .name = "erofs", .init_fs_context = erofs_init_fs_context,